The decision to bring Kara DioGuardi onboard the crazy train that is “American Idol” has, for the most part, been one met with support. That said, the reasoning behind adding a fourth judge might be slightly more complex than we’ve be lead to believe.

“They want another female in case Paula misses a taping,” a source close to the show told OK! magazine.

Another “Idol” source confirms that Abdul’s attendance last season was a source of extreme consternation.

“There were so many times they had to cover for Paula during the live shows. She’d just be totally MIA,” says a source who worked closely with Abdul. “We’d joke that the lady’s a flight risk. But really, she loves what she does. She wouldn’t just totally disappear. She’d come back — just maybe not in time for live television.”

DNC update: When the celebs really descended Sure, Denver played host to celebrities throughout the week of the DNC, but Aug. 27 and 28 had the greatest concentration of A-listers.

One of my favorite events of the week: the Aug. 27 live performance of Chris Moore’s documentary “The People Speak.” The documentary was inspired by the work of Howard Zinn and the readings that took place in Denver were performed by Ben Affleck, Taye Diggs, “W.” actor Josh Brolin and Rosario Dawson. (Jennifer Garner was in the audience; she was totally enthralled during Affleck’s reading. Adorable.)

Later in the night, Taye Diggs, Annette Bening, Seth Myers, Stuart Townsend and Forest Whittaker all attended the party thrown by the Impact Film Festival and the Screen Actors Guild at 5 Degrees restaurant. No drama, no divas, just a nice gathering.

Because I couldn’t be in two places at once, I missed the Jessica Alba sighting at Voto Latino’s DNC bash. “Dirty Delegate” martinis by Svedka vodka. Also there: Jennifer Lopez, Rosario Dawson, Fat Joe and Wilmer Valderrama.

I was surprised to hear that MySpace had set up an outpost in Denver, a la their MySpace café in Sundance. Eva Longoria made the café one of her first stops in Denver.

I spotted a very svelte Star Jones there, too, only she wouldn’t talk to me. Kudos to Jones’ publicist: This is the first time I’ve seen Jones pass up an interview because a reporter hadn’t gotten permission from her rep.

At the One Campaign’s Kanye West show, Affleck turned out as did Whittaker, and Steven Spielberg made a cameo. Points for Spielberg: The guy scored a pass for a local cab driver who was a big Kanye fan.

I’m sure I’ve left some out, but that’s OK. Next week it’s Minneapolis/St. Paul for the RNC and the big boldface names won’t be coming out in droves. I’ll save some for the slower days.

“It might be unfair calling Jessica Simpson’s show at the Avalon Ballroom Wednesday a train wreck — at some point, a train knows where it’s going,” said critic John Law in the Niagara Falls Review.

Law went on to criticize Simpson for oversharing. “I do pass gas a lot,” she told the crowd. “I guarantee it smells like roses.”

A former colleague of Simpson’s comes to her defense though: “She doesn’t care about that kind of stuff. She burps all the time, too. It’s just Jess,” says the source.

Weekend box officeThe last official weekend of the summer box office isn’t going to be an easy one to get right. First off, I should recognize that it is possible for “Tropic Thunder” to win again. If that happens, I will … I don’t know, but I think enough is enough already for this one. The new films this weekend include the new Vin Diesel sci-fi thriller “Babylon A.D.” It opens in 3,390 theaters. “Babylon” will lose some, but not many, tickets to spoof film “Disaster Movie” because they’re both rated PG-13. Yet another film with the magical rating: “Traitor” with Don Cheadle. The grim subject matter isn’t likely to do great the last weekend of summer, however, but any of the three films ought to do better than R-rated comedy “College.” It’s going to be close, but I’m going with “Babylon A.D.”

Courtney Hazlett delivers the Scoop Monday through Friday on msnbc.com.